Lasers are used for many purposes (e.g. etching, marking, cutting, and other heat or light related uses). For these purposes, alignment of the laser, for example for marking packages, requires alignment of the laser's output beam from the mounted position to the desired location. In conventional gas lasers, such as CO2 lasers, and some other laser types that use physically separate cavity mirrors, the laser beam is often not well aligned with the optical axis of the laser, and therefore not well aligned with the laser module housing the laser. Thus, when a laser in a production environment fails and is replaced with a new laser, some kind of re-alignment of the output beam is usually required. For example, the laser itself can be adjusted by adjusting the alignment of the cavity mirrors, or the laser module can be realigned as a whole so that the output beam points in the desired direction, or the output beam can be redirected by external optical components. This re-alignment is clearly not desirable. In some cases, users are provided with an in situ re-alignment component with a limited adjustment. Thus, when the output beam direction of the new unit diverges too far from center, there is often insufficient adjustment possible to re-align the output beam correctly. In these cases, customers reject the new unit completely and return it to the manufacturer as unusable.
It would thus be desirable to provide a laser module, in particular a gas laser module, in which the variation in output beam direction from unit to unit was minimized, or ideally minimal, so that the amount of beam adjustment needed would be kept low, or eliminated.